• Dr. Supriya S. Patil
• Dr. A. D. Shaligram

: Fiber optic displacement sensors are widely used in industry. These sensors however, have a limited linear operating range. A typical sensor constructed with 1 mm core diameter fibers has linear operating range of about 2-3 mm. Moreover, output of these sensors depends on the source intensity, reflector properties and fiber losses. Self referenced configurations of fiber optic displacement sensors are generally used to make the sensor immune to variation in source intensity or reflectivity of reflector etc. This paper reports a new fiber optic displacement sensor configuration which is similar to the self referencing arrangement and has wider operating range. During the experimentation with different arrangements of this type of sensor configuration, it is observed that different asymmetries have effect on the sensor performance parameters viz. sensitivity and linear operating range. Simulations are also carried out for these different configurations using the reported mathematical model. It is revealed from the theoretical analysis that a combination of asymmetries viz. different core radii of two receiving fibers and unequal horizontal offset leads to improvement in the sensor performance while maintaining the immunity advantage. A sensor probe is fabricated having transmitting fibers with 0.488 mm radius and two receiving fibers with 0.488mm and 0.75mm radius placed at distance of 0mm and 5mm respectively from the transmitting fiber is fabricated with movable mirror at a distance. The whole assembly is enclosed to get rid of stray light. Experiments are carried out using the developed sensor probe and proper signal conditioning circuit. Linearity of the Fiber optic displacement sensor is experimentally confirmed over the distance of 20mm. Thus it is said to have large stroke of 20mm and can act as a substitute for commercial transducer like LVDT.

self referenced fiber configuration, large stroke measurement, fiber optic sensor

"Large Stroke Fiber Optic Displacement Sensor Using Self Referencing Technique", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 5, page no.157-162, May-2019, Available :http://www.jetir.org/papers/JETIR1905823.pdf

"Large Stroke Fiber Optic Displacement Sensor Using Self Referencing Technique", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 5, page no. pp157-162, May-2019, Available at : http://www.jetir.org/papers/JETIR1905823.pdf